San Francisco is one of the most unaffordable cities in the nation with a median sales price of $925,000 in February. In an effort to keep low- and middle-income families from being priced out of the city by the tech boom, Mayor Ed Lee has announced a plan to double the maximum amount residents can qualify for in down payment assistance, from $100,000 to $200,000.

“Our city’s middle class is deeply affected by the housing crunch — they make too much to qualify for our traditional affordable housing, but not enough to afford much of the new market-rate construction,” Lee said.

The new limit will allow some homebuyers to afford homes costing $600,000 to $700,000, not enough for a home in a high-end neighborhood, but enough for some homes in more distant parts of the city.

Borrowers must be first-time buyers who make up to 120 percent of the area’s median income — $116,500 for a family of four. Borrowers must contribute at least 5 percent of the purchase price and the loans don’t need to be repaid until the borrower sells or refinances. At that time, the city takes a cut of the property’s appreciation.

San Francisco’s skyrocketing home prices and rents have sparked demonstrations from those who blame tech workers for gentrification in the city. Recently, protesters blocked shuttle buses taking workers to Google and Facebook and stopped at the San Francisco Association of Realtors’ headquarters on their way to a rally at City Hall.